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Flanagan, Mark F.
Preferred name
Flanagan, Mark F.
Official Name
Flanagan, Mark F.
Research Output
Now showing 1 - 4 of 4
- PublicationFundamental Limits of Spectrum Sharing for NOMA-Based Cooperative RelayingNon-orthogonal multiple access (NOMA) and spectrum sharing (SS) are two emerging multiple access technologies for efficient spectrum utilization in the fifth-generation (5G) wireless communications standard. In this paper, we present a closed-form analysis of the average achievable sum-rate and outage probability for a NOMA-based cooperative relaying system (CRS) in an underlay spectrum sharing scenario. We consider a peak interference constraint, where the interference inflicted by the secondary (unlicensed) network on the primary-user (licensed) receiver (PU-Rx) should be less than a predetermined threshold. We show that the CRS-NOMA outperforms the CRS with conventional orthogonal multiple access (OMA) for large values of peak interference power at the PU-Rx.
457Scopus© Citations 2 - PublicationFundamental Limits of Spectrum Sharing for NOMA-Based Cooperative Relaying under a Peak Interference ConstraintNon-orthogonal multiple access (NOMA) and spectrum sharing (SS) are two emerging multiple access technologies for efficient spectrum utilization in future wireless communications standards. In this paper, we present the performance analysis of a NOMA-based cooperative relaying system (CRS) in an underlay spectrum sharing scenario, considering a peak interference constraint (PIC), where the peak interference inflicted by the secondary (unlicensed) network on the primary-user (licensed) receiver (PU-Rx) should be less than a predetermined threshold. In the proposed system the relay and the secondary-user receiver (SU-Rx) are equipped with multiple receive antennas and apply selection combining (SC), where the antenna with highest instantaneous signal-to-noise ratio (SNR) is selected, and maximal-ratio combining (MRC), for signal reception. Closed-form expressions are derived for the average achievable rate and outage probabilities for SS-based CRS-NOMA. These results show that for large values of peak interference power, the SS-based CRS-NOMA outperforms the CRS with conventional orthogonal multiple access (OMA) in terms of spectral efficiency. The effect of the interference channel on the system performance is also discussed, and in particular, it is shown that the interference channel between the secondary-user transmitter (SU-Tx) and the PU-Rx has a more severe effect on the average achievable rate as compared to that between the relay and the PU-Rx. A close agreement between the analytical and numerical results confirm the correctness of our rate and outage analysis.
247Scopus© Citations 18 - PublicationGeneralized Least Squares Based Channel Estimation for High Data Rate FBMC-OQAMThis paper addresses the problem of preamble-based Channel Estimation (CE) in filter bank multi-carrier systems with offset quadrature amplitude modulation (FBMC-OQAM), a task that is problematic due to the presence of intrinsic Inter-Carrier Interference (ICI) and Inter-Symbol Interference (lSI). In this work, we present a theoretical analysis of the Mean Squared Error (MSE) of several CE schemes based on the virtual symbol (VS) approach such as the Interference Cancellation Method (ICM) and the Interference Approximation Method (IAM). We also propose and analyze a generalized least squares (GLS) based CE scheme which is capable of achieving improved performance by taking into account the correlation properties of the noise and interference among sub-carriers. Simulation results are presented which verify the accuracy of the theoretical analysis, and also demonstrate that the proposed GLS-based estimation method yields an improvement of almost 3dB in the CE-MSE with respect to the VS-based approach. Finally it is shown that, for higherorder modulation schemes, this CE-MSE reduction translates into significant improvement in the system's overall bit error rate (BER) performance with only minor additional complexity.
396Scopus© Citations 4 - PublicationOn Symmetry Properties of Intrinsic Interference in FBMC-OQAM SystemsFilter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) is a modulation technique which is widely considered as a strong contender to replace cyclic prefixed orthogonal frequency division multiplexing (CP-OFDM), for the future 5th generation (5G) of mobile wireless communication networks. FBMC-OQAM exhibits good spectral confinement properties, high spectral efficiency and immunity to synchronization errors, mainly due to its prototype filter's localization properties. But these desirable traits come with the loss of orthogonality, rendering it only orthogonal for real symbols with imaginary interference appearing in both the frequency and time domains. In this work, we prove a set of symmetry properties of this interference for a general class of FMBC-OQAM systems, and use these relationships to derive autocorrelation matrices for interference from neighboring symbols and also for noise contributions. These matrices find application in receiver design and also in channel estimation. The derived symmetry properties are also demonstrated through numerical examples for various standard prototype filter designs.
385Scopus© Citations 3